Records in events without World Athletics-ratified world records are typically referred to as world best performances or world bests. While races over imperial measured distances were very common in the first half of the 20th century, only the
mile remains common today due to its historical prominence in track and field: all other imperial measured distance races became increasingly rare, and the IAAF deleted these events from the world record books in 1976. In November 2019,
World Athletics (WA; formerly IAAF) also deleted several long-distance events (track distances of 20,000 metres, 25,000 metres and 30,000 metres and road distances of 15 km, 20 km, 25 km and 30 km) from the world record books. Some road racing distances and indoor variations of outdoor events fall outside of WA's lists, and records set in uncommon events usually do not adhere to the strict criteria found in WA-ratifiable events: one example is the 150 metres record, which was set by
Usain Bolt on a specially-made straight track, while previous performances (such as the
Bailey–Johnson 150-metre race) were completed on a traditional circuit which included a partial bend in the track. The
40-yard dash, a standard acceleration evaluation for
American football players, does not fall within the usual criteria of athletics racing events. In most 40-yard dashes, reaction times are not recorded as timing starts only once the player is in motion, and the standards for timing a "football 40" are so lax and inconsistent that a real world record cannot be claimed. Performances are also hand-timed and calculated to 1/100 of a second, although studies have shown human beings simply cannot react consistently or accurately enough for this to be a valid method, and even those using light beams are timed by the motion of the athlete, removing the normal factor of reaction time; further, football 40-yard dashes are usually run on a turf surface as opposed to an
all weather track. All of these factors make track and "football 40" performances essentially impossible to compare. The world best time for a "football 40" is 4.17 by
Deion Sanders, while the extrapolated best for an Olympic-level athlete (including reacting to a starting gun) is 4.24 by
Maurice Greene at the
2001 World Championships in Athletics. Under conventional football timing on a turf field in 2017,
Christian Coleman reportedly ran a 4.12.
Outdoor events Men } (37.524) (33.774) (30.195) (24.418) (29.921)
Women Mixed Indoor events Men }
Women Combined event disciplines World Athletics recognises world bests achieved in individual disciplines during a
combined event. The below list includes disciplines in the
decathlon (men) and
heptathlon (women). Athletes must score at least 7000 points in a decathlon in order to have their performance recognised.
Men Women ==Running records by race distance==